This invention relates to eyeglasses equipped with prismatic lenses. This invention relates particularly to eyeglasses for the visual rehabilitation and/or posture of a patient having for example visual-perceptual problems of orientation and/or space relation, of eyes-teeth-posture of the equilibrium relation along the trigeminal way.
Prisms are known, particularly yoked prisms. In the context of this description two prisms are defined yoked when both prisms are oriented with the bases in the same direction. The known yoked prisms have a dioptric power, generally measured in prism diopters, greater than 0.5. These prisms can be used by special eyeglasses intended to correct disorders and/or problems of spatial orientation, equilibrium-posture and general awareness of the patient wearing them. The eyeglasses equipped with prismatic lenses with dioptric power greater than 0.5, however, have some drawbacks. First of all, they show a considerable thickness which implies a particular discomfort in the assembly of prismatic lenses to the frame and also in the use of eyeglasses. These eyeglasses, if worn over a certain period of time (in the order of minutes), cause secondary effects to the patient wearing them, such as headaches and excessive muscle reactions (overtone), neurovegetative responses (nausea) and spatial distortions with difficulty and insecurity in the stability and gait. This inconvenience limits very much the use of these eyeglasses which, therefore, while having some beneficial effects for the patient who wears them they can be used often with discomfort and in patients with low average stiffness of visual-perceptual organisation and only for short periods of time.